Download Understanding your child`s hearing tests

Understanding your child’s
hearing tests
A guide to the hearing and medical
tests that are used to find out the type,
level and cause of deafness
Our vision is of a
world without barriers
for every deaf child.
Contents
1
Introduction
p4
2
The ear and how it works
p5
3
Different types of deafness
p6
4
Hearing tests
p7
5
Audiograms
p10
6
Hearing tests with hearing aids
p14
7
Causes of permanent deafness
p15
8
Medical tests used to help diagnose the cause of
permanent deafness
p16
9
Finding medical information on the internet
p24
Understanding your Child’s Hearing Tests
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1 Introduction
This booklet explains the different types and levels of deafness and includes
information on the variety of hearing tests that can be carried out to check a child’s
hearing. It explains about the ear and how it works, different types of deafness,
and audiograms. It also includes information on the different medical tests or
investigations that are used to help diagnose the cause of permanent deafness.
Students who are doing research about childhood deafness may also find this booklet
useful.
The guide is divided into different sections and each section has a different colour
border to the pages. This can help you go straight to the information you need. See
the Contents page ­for more information.
Throughout this booklet the reader is directed to other NDCS publications on relevant
topics for more information.
We produce a wide range of free publications on childhood deafness. For more
information or to order other publications, phone the NDCS Freephone Helpline on
0808 800 8880 or email [email protected]. Many publications are also available
to download from our website at www.ndcs.org.uk.
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2 The ear and how it works
The ear has two main functions.
• It receives sound and converts it into signals that the brain can understand.
• It helps us to balance.
The two functions are closely related.
The ear
The ear is the first part of the hearing system. The pinna (the outside part of the ear)
catches sound waves and directs them down the ear canal. The waves then cause the
eardrum to vibrate. These vibrations are passed across the middle ear by three tiny
bones: the malleus, incus and stapes (sometimes known as the hammer, anvil and
stirrup, known together as the ossicles). The bones increase the strength of the
vibrations before they pass through the oval window into the cochlea.
The cochlea looks like a snail’s shell. It is filled with fluid and contains thousands of
tiny sound-sensitive cells. These cells are known as hair cells. The vibrations entering
the cochlea cause the fluid and hair cells to move, much like the movement of
seaweed on the seabed when waves pass over it.
As the hair cells move, they create a small electrical charge or signal. The auditory
nerve carries these signals to the brain where they are understood as sound.
For an ear to work fully and allow us to pick up sound, all of these parts must work well.
Deafness happens when one or more parts of the system are not working effectively.
Balance
The brain uses information from the eyes (what we see), our body (what we feel) and
the inner ear to balance. The semicircular canals in the inner ear are three tubes, filled
with liquid and movement-sensitive hair cells. As we move, the fluid moves. This
creates signals that are sent to the brain about balance.
For more information about balance read our factsheet Balance and Balance Disorders.
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3 Different types of deafness
Conductive deafness is when sound cannot pass efficiently through the outer and
middle ear to the cochlea and auditory nerve. The most common type of conductive
deafness in children is caused by ‘glue ear’. Glue ear (or otitis media) affects about
one in five children at any time. Glue ear is a build-up of fluid in the middle ear. For
most children, the glue ear clears up by itself and does not need any treatment. For
some children with long-term or severe glue ear, hearing aids may be provided; or
the child may need surgery to insert grommets into the eardrums. Grommets are tiny
plastic tubes which are inserted into the eardrum. They allow air to circulate in the
middle ear and help to prevent fluid from building up.
For more information read our leaflet Glue Ear.
Sensori-neural (or nerve) deafness is when there is a fault in the inner ear (most
often because the hair cells in the cochlea are not working properly) or auditory
(hearing) nerve. Sensori-neural deafness is permanent.
Children who have a sensori-neural deafness can also have a conductive deafness
such as glue ear. This is known as mixed deafness.
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4 Hearing tests
There are a variety of tests that can be used to find out how much hearing your child
has. The tests used will depend on your child’s age and stage of development. It is
possible to test the hearing of all children from birth onwards. Screening tests are
normally done first to see if it is likely that there is a hearing loss and the child needs
to be referred to an audiologist. The audiologist will then perform more detailed tests
to build up an accurate picture of your child’s hearing.
You can ask your audiologist for a copy of your child’s test results. You may like
to keep them in your own file at home or take them with you when you visit the
audiology department or ear, nose and throat doctor.
Objective hearing tests
Otoacoustic emissions (OAE)
The otoacoustic emission test is commonly used
as part of the screening tests carried out on babies
shortly after birth. It works on the principle that a
healthy cochlea will produce a faint response when
stimulated with sound. A small earpiece (containing
a speaker and microphone) is placed in the child’s
ear. A clicking sound is played and if the cochlea
is working properly, the earpiece will pick up the
response. This is recorded on a computer and tells
the tester whether the child needs to be referred for
further tests.
A poor response to an OAE test does not necessarily
mean that a child is deaf. Background noise, an
unsettled baby, or fluid in the ear from the birth can
all make it difficult to record the tiny response.
Auditory brainstem response (ABR)
The audiologist will place three small sensors and a set of headphones on the child’s
head. For an accurate result, the child must be very still and quiet throughout the test.
In young babies the test can be carried out while they are sleeping. In slightly older
children, a light sedative or an anaesthetic may be offered.
This test measures whether sound is being sent from the cochlea and through the
auditory nerve to the brain. It can be used as a screening test (Automated Auditory
Brainstem Response – AABR – where the computer judges whether a response is
present at quiet levels of sound) or as a more detailed test where different levels of
sound are used and the audiologist interprets the results to find the quietest level of
sound being picked up by the hearing nerves.
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In very young children or children who are not developed enough to have behavioural
hearing tests, the results of the ABR test can be used to accurately fit hearing aids if
these are necessary. In older children this test may be used to confirm the results of
their behavioural test.
Behavioural tests
As your child grows older, their audiologist will get more information about your
child’s hearing through behavioural tests. These tests use toys and play as part of the
assessment and involve your child listening for a variety of sounds as part of a game.
Visual response audiometry (VRA)
Visual response audiometry is suitable for
children from six months to about two-anda-half years. Using a machine called an
audiometer, sounds of different frequencies
and loudness are played through speakers.
When the child hears the sound, they will turn
their head and a visual ‘reward’ is activated,
such as a toy lighting up or a puppet. The test
can check the full range of hearing but does
not give specific information about each ear.
If your audiologist feels it is important to get
information about each ear individually, this test
can be done with small earphones.
Pure tone audiometry
From about the age of three, children are
actively involved in testing by using a technique
known as conditioning. Younger children are
shown how to move a toy (for example, putting
a peg into a board) each time they hear a sound.
Older children are asked to respond to sounds
by saying yes or pressing a button. The sounds
come through headphones, earphones placed
inside the child’s ear, or sometimes through a
speaker (when the test is known as soundfield
audiometry).
Bone-conduction
All of the tests above are described as testing using air conduction (that is, sounds
passing through the ear canal and middle ear before reaching the cochlea). ABR,
VRA and PTA can also be tested using bone-conduction. A small vibrating device is
placed behind the child’s ear. This passes sound directly to the inner ear through the
bones in the head. This technique is useful for identifying whether a hearing loss is
conductive or sensori-neural.
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Speech discrimination tests
Speech discrimination tests check the child’s ability to hear words at different
listening levels. The tester asks the child to identify toys or pictures, or to copy
words spoken by themselves or from a recording. From this the tester can assess the
quietest level at which the child can correctly identify the words used. This test can
also be used to assess lipreading and signing skills.
Tympanometry
Tympanometry is not a test of hearing; it is used to check how well the moving parts
of the middle ear are working. A small earpiece is held gently in the ear canal. A pump
causes the pressure of the air in the ear canal to change. The eardrum should move
freely in and out with the change in pressure. The earpiece measures this by checking
the sound reflected by the eardrum. If the eardrum is not moving freely, there is likely
to be some fluid or another problem with the middle ear. This build-up of fluid is
usually glue ear (or otitis media). Glue ear can cause temporary conductive deafness.
For more information read our leaflet Glue Ear.
The line for a child without
glue ear is curved.
The line for a child
with glue ear is flat.
Hearing tests and children with additional
or complex needs
The tests used will depend on your child’s age as well as their stage of development.
It should be possible to test the hearing of any child, whatever their stage of
development, but it is more likely that several different tests will need to be done to
get a clear picture of any hearing difficulty. Objective tests (such as OAE and ABR)
do not need a child to respond to a sound in order to get a result. However, the child
needs to be very still and quiet throughout the test, which may mean they need a
light sedative or an anaesthetic.
Some children with additional needs may have to be tested using techniques that are
normally used with younger children. If your local audiology service is not confident
about testing your child, you can ask to be referred to another centre with more
experience of testing children with complex needs.
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5 Audiograms
Some of your child’s test results will be written on a chart like the one below, known
as an audiogram. It shows you how loud a sound has to be, and at what frequency,
before your child can hear it. Your child’s test results may be plotted on one chart (as
below) or two charts, side by side, for each ear separately. Crosses always indicate
results for the left ear, and circles for the right ear. Your child may be deaf in one ear
(unilateral deafness) or both ears (bilateral deafness). If your child is deaf in both
ears, the deafness may be similar in both ears (symmetrical deafness) or different in
each ear (asymmetrical deafness).
Your child’s deafness may also be described as high frequency or low frequency,
measured in hertz (Hz). We commonly think of frequency as the pitch of a sound. A
piano keyboard runs from low-pitch on the left to high-pitch sounds on the right and
the audiogram is the same.
There are different levels of deafness. These can be described as a decibel (dB)
hearing level (how loud a sound has to be for your child to hear it) or described using
terms such as ‘mild’, ‘moderate’, ‘severe’ or ‘profound’. The very quietest sounds are
at the top of the chart, getting louder as you look down the page.
Visual representation of the loudness and pitch of a range of everyday sounds
Frequency in Hertz (Hz)
Low
125
-10
Levels of
deafness:
High
PITCH
250
500
1000
0
2000
4000
F
10
F
L O R R Y
Mild
deafness
21 - 40 dB
L O R R Y
Moderate
deafness
41 - 70 dB
BAND
Severe
deafness
71 - 95 dB
B
U
Z
Z
Hearing level in decibels (dB)
20
F
f sth
F
zv
L O R R Y
p
hg
ch
sh
B
U
Z
Z
30
F
8000
L O R R Y
BAND
B
U
Z
Z
j
40
F
BAND
mdb
n
ng
el
u
B
U
Z
Z
L O R R Y
k
B
U
Z
Z
BAND
i
oa r
BAND
50
L O R R Y
B
U
Z
Z
BAND
60
F
L O R R Y
70
B
U
Z
Z
BAND
80
F
F
90
L O R R Y
F
F
L O R R Y
F
F
F
F
Profound
deafness
95+ dB
100
B
U
Z
Z
F
B
U
F
L O R R Y
L O R R Y
Z
Z
BAND
L O R R Y
BAND
Loud
sounds
L O R R Y
L O R R Y
110
L O R R Y
B
B
L O R R Y
U
U
Z
Z
Z
Z
L O R R Y
B
BAND
BAND
U
Z
Z
B
U
B
Z
120
Z
U
B
U
Z
BAND
Z
B
Z
Z
U
Z
BAND
Z
BAND
BAND
B
U
Z
BAND
Z
BAND
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Understanding your Child’s Hearing Tests
On the audiogram on page 10 there are pictures of common sounds that give us an
idea of loudness and frequency. There are also speech sounds drawn on the chart,
and you can see that all the sounds of speech cover a range of frequencies. Try saying
some of the speech sounds out loud while looking at the chart. The sounds m, b, and
d are on the left-hand side and part way down the chart, meaning that they are lower
frequency and slightly louder than say f, s, and th, which are higher in frequency and
much quieter. So it is important to be able to hear sounds at a quiet level, across the
frequency range, to be able to hear all the sounds of speech clearly.
Ask your child’s audiologist to explain your child’s hearing test results to you and
how they will affect your child’s ability to hear speech.
Some examples of different audiogram results
Typical range of hearing
This audiogram shows the level and range for a person with typical hearing levels.
Frequency in Hertz (Hz)
125
-10
Results above the line represent
typical hearing levels
250
500
1000
2000
4000
0
X Left Ear
10
Right Ear
8000
X
X
X
X
X
X
Hearing level in decibels (dB)
20
30
40
50
60
70
80
90
100
110
120
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Frequency in Hertz (Hz)
250
500
1000
]
2000
4000
]
X
X
X
X
X
X
] Bone conduction test
Sensori-neural deafness in the right ear
This audiogram shows a
sensori-neural deafness in
125
-10
the right ear. You can see
that both the air- and
0
bone-conduction tests
10
give similar results.
8000
]
]
Hearing level in decibels (dB)
Conductive deafness in the left ear
This audiogram shows a
typical conductive deafness
125
in a child’s left ear. There
-10
are two lines – one shows
0
the result of air-conduction
tests (with headphones or
10
earphones in the ears)
20
marked by crosses, and the
other shows bone30
conduction results marked
40
by square brackets ([). The
bone-conduction test
50
shows that the inner ear is
60
receiving the signal clearly,
but the air-conduction test
70
shows that the sound is
80
being blocked by fluid or
another obstruction in the
90
outer or middle ear. This
100
child may have a temporary
conductive deafness as a
110
result of glue ear or a
120
permanent conductive
deafness.
X Air conduction test
Frequency in Hertz (Hz)
250
500
1000
2000
[
[
4000
8000
Hearing level in decibels (dB)
20
30
40
50
[
[
60
70
80
90
100
110
120
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[ Bone conduction test
Air conduction test
Understanding your Child’s Hearing Tests
Mixed deafness in the right ear
Frequency in Hertz (Hz)
125
-10
250
500
1000
2000
4000
8000
0
10
20
Hearing level in decibels (dB)
This last audiogram
gives an example of
mixed deafness in the
right ear. Both the
bone-conduction and
air-conduction tests
show that there is a
hearing loss. Because
the results are very
different, this child has
more than one cause of
deafness.
[
[
30
40
[
[
50
60
70
80
90
100
110
120
Understanding your Child’s Hearing Tests
[ Bone conduction test
Air conduction test
The National Deaf Children’s Society
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6 Hearing tests with
hearing aids
If your child does have a hearing loss, they may be fitted with hearing aids. VRA,
soundfield audiometry and speech testing can all be used while wearing hearing
aids, and the results provide some information about what your child can hear with
them. When these results are written down, they are called ‘aided responses’. ‘Real
ear measurements’ will also be used to make sure the hearing aid’s settings are as
close as possible to your child’s hearing loss.
Real ear measurements (REM)
Your child’s hearing aids will be programmed for each child’s hearing loss. Two
children with identical hearing losses and identical hearing aids will have slightly
different prescriptions. This is because the size of each child’s ear canal will vary,
and this can alter the signal (or frequency response) coming from the hearing aid.
The audiologist will use a ‘probe tube microphone’ to take measurements in your
child’s ear canal to make sure that the hearing aid is set correctly.
(This type of testing is not suitable for children who use bone-conductor hearing
aids.)
Other methods of assessing the benefit of hearing aids
Your audiologist or teacher of the deaf will go through a questionnaire or checklist
with you and your child to find out how well your child listens in different situations
with the hearing aid (for example, how they are at identifying different sounds at
home, working in groups at school, or using the phone). If your child is very young,
your observations using the Common Monitoring Protocol in your Early Support
Family Pack may be used. The results of these can be used to fine-tune the settings
of the hearing aids if necessary.
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Understanding your Child’s Hearing Tests
7
Causes of permanent
deafness
There are many reasons why a child can be born deaf or become deaf early in life. It is
not always possible to identify the reason, but you may be offered further tests to try
and establish the cause of your child’s deafness.
Causes before birth (pre-natal causes)
Around half the deaf children born in the UK every year are deaf because of a genetic
(inherited) reason. Deafness can be passed down in families, even though there
appears to be no family history of deafness. For about 70% of these deaf children,
no other problems will occur. For the other 30%, the gene involved may cause other
disabilities or health problems.
Deafness can also be caused by complications during pregnancy. Infections such as
rubella, cytomegalovirus (CMV), toxoplasmosis and herpes can cause a child to be
born deaf. There are also a range of medicines, known as ototoxic drugs, which can
damage a baby’s hearing system before birth.
Causes in early childhood (post-natal causes)
Being born prematurely can increase the risk of a child being deaf or becoming deaf.
Premature babies are often more prone to infections that can cause deafness. Severe
jaundice or a lack of oxygen at some point can also cause deafness. Infections during
early childhood, such as meningitis, measles and mumps, can be responsible for a
child becoming deaf.
Occasionally, a head injury or exposure to loud noise can damage the hearing system.
For more information about the tests used to find out the cause of deafness, read
section 8.
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8 Medical tests used to help
diagnose the cause of
permanent deafness
This section tells you about the range of medical tests that can be carried out to try to
find the cause of your child’s deafness. The process to find out why a child is deaf is
sometimes called an ‘aetiological investigation’.
The tests listed in this section can find the reason for a child’s deafness in 40% to
50% of cases. For the other 50% to 60% of cases it is not possible to find out why a
child is deaf. If it is not possible to find out the cause of your child’s hearing loss, it
may be helpful for you to know what did not cause it.
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Doctors may sometimes suggest tests on other parts of your child’s body, like the
kidneys or heart, to help identify the cause or rule out certain conditions that can
be associated with deafness. Deafness can be part of a ‘syndrome’ (syndrome is
a medical term meaning a collection of symptoms or signs that commonly appear
together).
It is important to know about any associated medical conditions so you can consider
appropriate treatment or ways of managing the deafness or condition. However,
these conditions are relatively rare in deaf children and extremely rare in the
population as a whole.
As with many services provided by the NHS, for some tests you may be asked to give
your written permission first.
Throughout this section we use the following terms:
• ‘Your doctor’ to mean the doctor in charge of your child’s audiological care. This may be an audiological physician, ENT specialist, or community paediatrician in audiology.
• ‘Your family’ includes your child’s grandparents on both sides.
We would like to thank the members of the Aetiological Investigations Group for the
valuable advice they gave to help us produce the information in this section.
What happens when you see the doctor?
The doctor will take details of your child’s medical history. This will include questions
about the pregnancy, including any medication that was taken during the pregnancy
and the mother’s health before, during, and after the birth.
The doctor will ask you about your child’s immunisations (routine baby jabs). In
toddlers and older children, the doctor will ask about your child’s development
(including speech, language and milestones such as when your child was sitting,
walking and so on). The doctor may also ask about whether your child has:
• had meningitis, mumps, measles or other illnesses
• been exposed to loud noises
• taken any prescribed medication
• suffered any head injuries
• had any ear infections
• had sight problems
• had balance problems.
All of these factors are important when investigating the cause of deafness.
The doctor will also ask about the hearing of other family members, on both sides of
the family.
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Physical examination
The doctor will look at your child’s head and face area and may also take some
measurements. The doctor will also look at your child’s neck, skin, nails, arms, legs,
chest, abdomen (tummy), eyes, mouth, palate (roof of the mouth) and ears. They are
looking for any minor differences or signs (for example, tiny holes in the skin known
as ‘pits’), that may help to diagnose the cause of the deafness. The doctor will assess
your child’s development in relation to the expected ages and stages (see your baby’s
Personal Child Health Record – the Red Book – for further information on this).
The doctor may ask close family members to have a hearing test, known as an
audiogram.
Imaging
Imaging is a general term covering different ways of looking at parts inside the body
(such as bones or major organs) and how they are working.
The doctor uses an MRI (magnetic resonance imaging) scan or a CT (computerised
tomography) scan to look at the structure of the ear and hearing nerve as well as
other parts of the body that may be associated with the deafness. Both types of scan
are commonly used with children who have deafness.
An MRI scan will show soft tissues including the brain and hearing nerve. It will show
if the hearing nerve has developed normally. MRI scans use magnets and radio waves
to produce detailed pictures of the inside of the body. There are no known side effects
associated with this type of scan. An MRI scan can be carried out on a child from birth,
but you should be offered a choice of when the scan is done. If it is important for your
child to have the scan, the doctor will explain this to you.
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A CT scan will show the bony parts of the ear including the ‘ossicles’ (the three tiny
bones in the middle ear) and the ‘cochlea’ (the inner ear). A CT scan will show if
the bony parts have developed normally. A CT scan involves exposing your child to
radiation in the form of X-rays. The level of radiation used is kept as low as possible
to prevent damage to body cells, and the amount of radiation your child is exposed
to depends on the number of images taken. It is generally accepted that there is little
risk to health from one scan, but with repeated tests there is a risk that the radiation
may damage body cells. There is only a risk if your child has a high number of x-rays
or scans. The earlier in life your child is exposed to radiation, the greater the risk. You
and the doctor may prefer to wait until your child is a little older. Your child’s doctor
will discuss this with you and answer any questions you may have.
Your child will need to be absolutely still for the
time it takes to do a CT or MRI scan. Very young
babies may be able to have these scans while
they are asleep. Each hospital will have its own
procedure, and your doctor will explain this to
you. Generally, children aged over three months
will normally be given something to help them
sleep. This may be a light sedative or a short
general anaesthetic.
For children aged over two, you may be offered
a stronger sedative or a general anaesthetic.
Although modern anaesthetics are extremely
safe, there are small risks associated with
having an anaesthetic and your doctor should
explain these to you. The risks of having an
anaesthetic reduce as the child gets older.
Usually, children over the age of five can lie
still for the scan without needing a sedative or
anaesthetic.
A further type of scan that may sometimes be used is a renal ultrasound. This is a
scan that uses sound waves to create images of the kidneys. It is similar to the scans
used during pregnancy. It is only likely to be used to rule out a rare syndrome or if
there is a family history of kidney problems. There are no risks associated with this
type of scan.
Your doctor may recommend that one or more of the above scans are done at an
early stage, for example, if:
• your child has had meningitis
• your child is being referred to be assessed for a cochlear implant
• the deafness is getting worse or changing over time
• there are characteristic features that may suggest your child’s deafness could be part of a ‘syndrome’.
In these examples, your doctor will need to look closely at the structure of the cochlea
(inner ear) and hearing nerve to be able to give you advice on possible management
or treatment options.
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Electrocardiography (ECG)
An ECG is a recording of the rhythm and electrical activity of the heart. There is a very
rare syndrome linking severe and profound hearing loss to a heart problem. If this
heart problem is detected it can be treated.
Depending on your child’s and your family’s medical history, your doctor may advise
an ECG for a small number of children with severe to profound deafness to help rule
out this condition. There are no risks associated with having this test.
Blood and urine tests
Depending on your child’s and your family’s medical history, the doctor may ask for
one or more routine blood and urine tests. These tests can help doctors to identify the
cause of the deafness.
An example of a blood or urine test your child may be offered is an infection screen.
An infection screen is used to look for certain infections that sometimes result in
deafness. Some of these tests will give useful results only if they are carried out in the
weeks or months shortly after your child’s birth. When the child is older, an infection
screen may give a negative result and rule out an infection being the cause of the
deafness. However, a positive result later in life may not give useful information as
your doctor could not prove that the infection was present at birth and so caused the
deafness.
There are several infections that
can cause deafness in babies if
the mother contracts them when
pregnant. The most common
infection causing babies to
be born with deafness is CMV
(cytomegalovirus). CMV is very
common in the general population
and does not normally cause any
illness. However, it can affect the
baby if the mother catches it while
pregnant. CMV infection in an
unborn baby is called ‘congenital
CMV’. (‘Congenital’ means from
birth.) About one baby in every
200 is born with CMV and some
of these babies can be affected
by it. Congenital CMV can cause
deafness or, very occasionally, it
can affect a child’s development.
Congenital CMV causes about 10%
to 20% of deafness in children in
the UK. Doctors can test for CMV
in the first few weeks after birth,
or for older children look for signs
of the CMV infection in the
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heel-prick blood test cards which are stored after birth. Deafness following infection
can sometimes get worse over time. If a young baby is found to have the CMV
infection, it may be possible to give treatment that may prevent the deafness from
increasing.
For more information you may like to read our leaflet Congenital Cytomegalovirus and
Deafness.
Less common infections that can cause deafness include rubella (German measles),
toxoplasma and syphilis. Your doctor will be able to give you more information about
these infections. All the blood tests are usually done using one blood sample.
Ophthalmology (eye test)
All children learn from what they see and hear around them. Children who are deaf
rely on their eyesight even more than other children do. Up to 40% of children with
sensori-neural deafness also have an eye problem. This may simply mean the child
will need to wear glasses when they are older, but an eye test can also help to
diagnose a syndrome associated with deafness. As babies can’t tell us what they
can see, a developmental assessment of the eye is done to make sure the eyes are
healthy. Sometimes special eye tests are used. Your opthamologist (eye doctor) will
discuss this with you if necessary. It is recommended that all children diagnosed with
deafness are referred for an eye test and have regular eye tests throughout their
childhood.
For more information about eye tests you may like to read our leaflet Vision Care for
your Deaf Child.
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Genetic counselling
Just as children inherit features such as hair colour or eye colour from their parents,
sometimes deafness is inherited.
If your child’s deafness could have a genetic cause, you should be given the chance
to discuss this with a trained genetics counsellor. Genetic counselling gives families
information about:
• the cause of a range of inherited conditions
• how an inherited condition might affect the child and family in the future
• how likely you are to have another child with the same condition.
Some families find it helpful to know whether the deafness and any other medical
condition were inherited. Other families prefer to wait until their children are grown up
and able to decide for themselves.
For more information you may like to read our leaflet Genetic Counselling: Information
for families.
Genetic testing
You may be offered a genetic test. This will involve your child, and possibly other
family members, having a blood test.
The blood sample will be used to look for the gene or genes known to be involved
with deafness. Not all the genes related to deafness have been identified and for
most there is not yet a routine test. This means that even if the deafness is inherited,
it may not be possible to confirm this with a genetic test at the moment. About 50%
of children with permanent deafness have a genetic cause. In about 30% of children
with a genetic deafness, the deafness is part of a syndrome. Again, some of these
syndromes can be confirmed with a genetic test, but many cannot.
Some children have a rare genetic deafness that can get worse if they are given
certain medications. It is possible to have a genetic test to identify whether they have
this gene. If they do, then this information will help inform you and your doctor if, in
the future, your child needs treatment. Your doctor may recommend that this test is
done at an early stage depending on your child’s history.
Your doctor may refer you to a clinical geneticist or a genetic counsellor. Alternatively,
they may discuss genetic testing with you themselves. Individual health authorities
decide whether to offer routine genetic testing through the audiology or ENT
department. Some areas offer genetic testing through this route only if it would
provide a direct benefit to the child being tested. For example, if the child has an
inherited medical condition it may be of direct benefit to have a genetic test. This is
because the results may help to identify treatments that should be made available
to the child. Your doctor will discuss the options available in your area with you. If
you want to ask more about genetic testing, you can ask to be referred to your local
clinical genetics service and your doctor will discuss with you if this is appropriate.
For more information on the genetics of deafness you may like to read our leaflet
Genetic Counselling: Information for families.
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What next?
Some or all of the tests in this section will be offered to your child, not necessarily in
the order given here. Your doctor will give you more information which will help you
decide whether you want your child to have the available tests and the best time for
the tests to be carried out. Test results that may offer immediate benefit to a baby are
best done at an early stage, for example when the infection screen is carried out.
Some tests (for example, some routine genetic testing) will not offer an immediate or
direct benefit to a baby and may be delayed until a later stage. Your doctor will tell
you if particular tests should be done (for example, if your doctor suspects that your
child’s deafness is part of a syndrome). You and your doctor can use this information
when planning how to manage the hearing loss and any associated condition in the
future.
Most of the tests are not urgent. It is important that you feel comfortable with your
child having them. Discuss any worries with your doctor.
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9 Finding medical
information on the internet
Thanks to Contact a Family for letting us reproduce this information from their leaflet
Finding Medical Information on the Internet. You can find the full consumer guidelines at
www.northumbria.ac.uk/sd/academic/ceis/re/isrc/themes/ibarea/ju/
The internet can be a very useful source of information for families, but the number and
types of websites can cause confusion. The aim of this section is to help you decide
whether a website provides relevant, high quality information.
What to look for on support group websites.
Support groups’ websites allow you to get in touch with other people.
Consider the following.
•Can you find clear contact details for the organisation that set up the website?
•If there are email lists, bulletin boards and chat rooms, you are likely to be in touch
with people who are genuine. But remember, some may have extreme views.
•Check that your personal information will be kept secure and not shared with
others.
•See if your personal details are being recorded when you visit the website.
•Can you contact the website manager to report technical problems and provide
comments about the site?
The NDCS has an online discussion group called Parent Place, where
parents and other family members share information and practical
advice.
How reliable is the medical information?
Consider the following:
•Check the author’s name, job title, workplace, and any formal or professional
qualifications.
•Check the date the information was put on the site. Medical information can become
out of date very quickly.
•Is the information aimed at getting you to buy something?
•Does the information acknowledge that specific conditions affect people in different
ways, ranging from mild to severe?
•Check whether the information is based on a person’s own experiences. How the
condition affects your child may differ from other people’s experiences.
•Does the information sound extreme?
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Who is the website for?
•Websites are aimed at different groups of people (for example, professionals,
academics, members of the public). Detailed pieces of academic research can be
confusing, and may not be helpful. Think about who the website is aimed at and
how useful the information will be.
Who produced the website?
Websites can be set up by anybody, from respected organisations and experts to
people with extreme views and companies trying to sell you something.
Consider the following:
•Look for the name, address and contact details of the organisation.
•Does the organisation have a registered charity number (if relevant)?
•What are the aims and purpose of the organisation?
•Check the names and qualifications of any professionals contributing to the
website. Is there an Advisory Panel or Review Group?
•Websites should state clearly if the information is based on people’s personal
experiences.
•Websites sponsored by commercial organisations may be biased towards certain
treatments or products. Adverts that appear on a website might also reflect this.
Websites from outside the UK can be useful, but may refer to medicines using different
names from those used here, or ones not licensed for use in this country. There may be
different medical practice and treatments in other countries.
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Notes
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NDCS provides the following services through our membership scheme.
Registration is simple, fast and free to parents and carers of deaf children
and professionals working with them. Contact the Freephone Helpline
(see below) or register through www.ndcs.org.uk
• A Freephone Helpline 0808 800 8880 (voice and text) offering clear, balanced
information on many issues relating to childhood deafness, including schooling and communication options.
• A range of publications for parents and professionals on areas such as audiology, parenting and financial support.
• A website at www.ndcs.org.uk with regularly updated information on all aspects of childhood deafness and access to all NDCS publications.
• A team of family officers who provide information and local support for families of deaf children across the UK.
•
Specialist information, advice and support (including representation at hearings if needed) from one of our appeals advisers in relation to the following types of
tribunal appeals: education (including disability discrimination, special educational
needs (SEN) and, in Scotland, Additional Support for Learning (ASL)); and benefits.
• An audiologist and technology team to provide information about deafness and equipment that may help deaf children.
• Technology Test Drive – an equipment loan service that enables deaf children to try
out equipment at home or school.
• Family weekends and special events for families of deaf children.
• Sports, arts and outdoor activities for deaf children and young people.
• A quarterly magazine and regular email updates.
• An online forum for parents and carers to share their experiences at www.ndcs.org.uk/parentplace.
• A website for deaf children and young people to get information, share their
experiences and have fun at www.buzz.org.uk.
NDCS is the leading charity dedicated to creating
a world without barriers for deaf children and
young people.
NDCS Freephone Helpline:
0808 800 8880 (voice and text)
[email protected]
JR0371
www.ndcs.org.uk
Published by the National Deaf Children’s Society
15 Dufferin Street, London EC1Y 8UR ISBN 978-1-907814-01-3
Tel: 020 7490 8656 (voice and text) Fax: 020 7251 5020
NDCS is a registered charity in England and Wales no. 1016532
and in Scotland no. SC040779 © NDCS REPRINT November 2013
This publication can be requested in large print, in Braille and on audio CD.